Hello Dan,
I use both FIrefox and Chrome browsers and also with both Windows10 and Linux Ubuntu and I get the same result with both,
I attach screen shot using windows10 and Chrome for reference.
The button you are looking for is the video camera icon in the bottom right of the live view window, if you click that once it will turn red to show that live view is being recorded, click it again and the recording will stop and be downloaded to your chosen file location (file location can be set in the local menu).
Hello Dan,
I have just found the Record icon on the lower right hand side of the window using Windows10 and Chrome.
Thanks for the nudge in the right direction for the solution.
Linux, like MacOS, is not fully supported by Hikvision so you can see certain settings and features missing when accessing the NVR/cameras with browsers on these operating systems.